1. Field of the Invention
The present invention relates broadly to power tools and, more particularly, to a powered adjustable wrench having a sliding side jaw.
2. Description of the Prior Art
A powered adjustable jaw wrench having a sliding side jaw and a stationery jaw is known in the prior art. As illustrated in FIG. 1, a fixed jaw 2 is integral with the wrench head 3 and a movable jaw 4 is adjustable relative to the fixed jaw. A worm gear 5 having a pulley 6 is rotated by a belt 7 and a motor pulley 8. The adjustable jaw 4 is provided with an integral gear rack for engagement with the worm gear 5. The worm gear 5 is positioned between the fixed jaw 2 and the pulley 6. A double pole double throw (DPDT) switch 9 is used to control the opening and closing of the movable jaw 4. With an upper handle housing removed, a bottom handle housing 10 houses an electric motor 12 connected to the motor pulley 8 by a shaft 13. Wires 14 and 15 connect the electric motor 12 with the DPDT switch 9 and batteries 16 supply power for the switch and motor. A sub mini jack 18 is used for recharging the batteries 16. The bottom handle housing 10 defines a battery recess 19 and a motor recess 20 containing the motor 12.
However, wrenches of this type suffered certain drawbacks owing to a tendency of the adjustable jaw to jam when xe2x80x9cbindingxe2x80x9d occurs between the adjustable jaw gear rack and the worm gear. One of the reasons of the xe2x80x9cbindingxe2x80x9d to occur is the positioning of the pulley 6 relative to the fixed jaw 2. When utilizing an adjustable wrench for either tightening or loosening, there are forces applied between the worm gear 5 and the moveable jaw 4. The pressure that is applied from the moveable jaw rack, pushes the worm gear 5 away from the stationary jaw creating a binding condition between the worm gear 5 and the moveable jaw rack. Furthermore, when the moveable jaw 4 is fully extended, only part of worm gear leads are engaging the moveable jaw rack, because the moveable jaw rack can not fully extend due to position of the pulley 6 relative to the fixed jaw 2 and the worm gear 5, as described above and illustrated in FIG. 1. Thus, wrench-tends to bind in its fully open position due to lack of full engagement of the worm gear to the moveable jaw rack.
The present invention is an improvement over the powered adjustable jaw wrench of the prior art disclosed in U.S. Pat. No. 4,512,221 incorporated herein by reference.
It is therefore an object of the present invention to provide for a novel and improved powered adjustable jaw wrench including an anti-jamming coupling device provided for un-jamming the wrench when xe2x80x9cbindingxe2x80x9d occurs between a gear rack of an adjustable jaw and a worm gear.
In accordance with the present invention, the powered adjustable jaw wrench includes a unitary single-piece body member having integral elongated handle portion and a head portion, a stationary jaw defined by the head portion, a movable jaw adjustable relative to the stationary jaw, actuated by a driven mechanism comprising a worm gear rotatably mounted in said head portion of said body member for advancing the movable jaw toward and away from the stationary jaw, and a first rotatable member drivingly coupled to the worm gear, a drive mechanism including a power source, and the anti-jamming coupling device provided for operably connecting the first rotatable member to the worm gear. The anti-jamming coupling device includes a drive member drivingly connected to the first rotatable member and a driven member drivingly connected to the worm gear. The drive member drivingly engages the driven member when the powered adjustable jaw wrench is activated by striking the driven member in order to upset the worm gear when jammed.
In accordance with the first embodiment of the present invention, the first rotatable member of the driven mechanism is a toothed sprocket drivingly coupled to the worm gear, and the drive mechanism comprises a reversible electric motor driving a second sprocket rotating the first sprocket through a toothed belt. A control switch assembly for controlling the electric motor is provided at the handle portion of the wrench body. The wrench body member defines a cavity housing the electric motor and electric batteries supplying an electric power to said electric motor. A handle cover is used to seal the cavity.
In accordance with the second embodiment of the present invention, the wrench body includes a unitary single-piece body member and a pair of opposite handle covers.
In accordance with the third embodiment of the present invention, the drive mechanism includes a chain drive mechanism.
In accordance with the forth embodiment of the present invention, the drive mechanism further includes a speed reduction gearing disposed between the electric motor and the second sprocket.
In accordance with the fifth embodiment of the present invention, the reversible electric motor is disposed in the head portion of the wrench body member.
In accordance with the sixth embodiment of the present invention, the wrench body further include a solar panel (i.e., a battery of solar cells) for recharging the electric batteries.
In accordance with the seventh embodiment of the present invention, the wrench further includes an illumination device mounted to the wrench body and adapted to provide direct illumination a work area in order to facilitate operation in a dark environment.
In accordance with the eighth embodiment of the present invention, the drive mechanism includes a fluid pressure motor as a power source.
In accordance with the ninth embodiment of the present invention, the powered adjustable jaw wrench includes a fluid-pressure turbine for driving the worm gear. The turbine is fluidly connected to a source of pressurized fluid through a fluid flow control valve for controlling direction of rotation of said fluid-pressure turbine. The source of pressurized fluid may be any appropriate external source of pressurized fluid, such as pneumatic pump or compressor.
The tenth embodiment of the present invention is similar to the ninth embodiment wherein the source of pressurized fluid is a pressurized gas cartridge disposed within the handle portion of the wrench body member.
In accordance with the eleventh embodiment of the present invention, the powered adjustable jaw wrench includes a pair of fluid-pressure turbines provided for driving the worm gear. The first turbine is adapted to rotate the worm gear in a clockwise direction, while the second turbine is adapted to rotate the worm gear in a counterclockwise direction.